And so, one day, Mary’s captors decided it was time for her to see colors. As a trick, they prepared a bright blue banana to present as her first color experience ever. Mary took one look at it and said “Hey! You tried to trick me! Bananas are yellow, but this one is blue!” Her captors were dumfounded. How did she do it? “Simple,” she replied. “You have to remember that I know everything—absolutely everything—that could ever be known about the physical causes and effects of color vision. So of course before you brought the banana in, I had already written down, in exquisite detail, exactly what physical impression a yellow object or a blue object (or a green object, etc.) would make on my nervous system. So I already knew exactly what thoughts I would have (because, after all, the “mere disposition” to think about this or that is not one of your famous qualia, is it?). I was not in the slightest surprised by my experience of blue (what surprised me was that you would try such a second-rate trick on me). I realize it is hard for you to imagine that I could know so much about my reactive dispositions that the way blue affected me came as no surprise. Of course it’s hard for you to imagine. It’s hard for anyone to imagine the consequences of someone knowing absolutely everything physical about anything!”

I don’t intend to fully analyze this scenario here, and for that reason I left it to the reader in the previous post. However, I will make two remarks, one on what is right (or possibly right) about this continuation, and one on what might be wrong about this continuation.

The basically right or possibly right element is that if we assume that Mary knows all there is to know about color, including in its subjective aspect, it is reasonable to believe (even if not demonstrable) that she will be able to recognize the colors the first time she sees them. To gesture vaguely in this direction, we might consider that the color red can be somewhat agitating, while green and blue can be somewhat calming. These are not metaphorical associations, but actual emotional effects that they can have. Thus, if someone can recognize how their experience is affecting their emotions, it would be possible for them to say, “this seems more like the effect I would expect of green or blue, rather than red.” Obviously, this is not proving anything. But then, we do not in fact know what it is like to know everything there is to know about anything. As Dennett continues:

Surely I’ve cheated, you think. I must be hiding some impossibility behind the veil of Mary’s remarks. Can you prove it? My point is not that my way of telling the rest of the story proves that Mary doesn’t learn anything, but that the usual way of imagining the story doesn’t prove that she does. It doesn’t prove anything; it simply pumps the intuition that she does (“it seems just obvious”) by lulling you into imagining something other than what the premises require.

It is of course true that in any realistic, readily imaginable version of the story, Mary would come to learn something, but in any realistic, readily imaginable version she might know a lot, but she would not know everything physical. Simply imagining that Mary knows a lot, and leaving it at that, is not a good way to figure out the implications of her having “all the physical information”—any more than imagining she is filthy rich would be a good way to figure out the implications of the hypothesis that she owned everything.

By saying that the usual way of imagining the story “simply pumps the intuition,” Dennett is neglecting to point out what is true about the usual way of imagining the situation, and in that way he makes his own account seem less convincing. If Mary knows in advance all there is to know about color, then of course if she is asked afterwards, “do you know anything new about color?”, she will say no. But if we simply ask, “Is there anything new here?”, she will say, “Yes, I had a new experience which I never had before. But intellectually I already knew all there was to know about that experience, so I have nothing new to say about it. Still, the experience as such was new.” We are making the same point here as in the last post. Knowing a sensible experience intellectually is not to know in the mode of sense knowledge, but in the mode of intellectual knowledge. So if one then engages in sense knowledge, there will be a new mode of knowing, but not a new thing known. Dennett’s account would be clearer and more convincing if he simply agreed that Mary will indeed acknowledge something new; just not new knowledge.

In relation to what I said might be wrong about the continuation, we might ask what Dennett intended to do in using the word “physical” repeatedly throughout this account, including in phrases like “know everything physical” and “all the physical information.” In my explanation of the continuation, I simply assume that Mary understands all that can be understood about color. Dennett seems to want some sort of limitation to the “physical information” that can be understood about color. But either this is a real limitation, excluding some sorts of claims about color, or it is no limitation at all. If it is not a limitation, then we can simply say that Mary understands everything there is to know about color. If it is a real limitation, then the continuation will almost certainly fail.

I suspect that the real issue here, for Dennett, is the suggestion of some sort of reductionism. But reductionism to what? If Mary is allowed to believe things like, “Most yellows typically look brighter than most blue things,” then the limit is irrelevant, and Mary is allowed to know anything that people usually know about colors. But if the meaning is that Mary knows this only in a mathematical sense, that is, that she can have beliefs about certain mathematical properties of light and surfaces, rather than beliefs that are explicitly about blue and yellow things, then it will be a real limitation, and this limitation would cause his continuation to fail. We have basically the same issue here that I discussed in relation to Robin Hanson on consciousness earlier. If all of Mary’s statements are mathematical statements, then of course she will not know everything that people know about color. “Blue is not yellow” is not a mathematical statement, and it is something that we know about color. So we already know from the beginning that not all the knowledge that can be had about color is mathematical. Dennett might want to insist that it is “physical,” and surely blue and yellow are properties of physical things. If that is all he intends to say, namely that the properties she knows are properties of physical things, there is no problem here, but it does look like he intends to push further, to the point of possibly asserting something that would be evidently false.

The lasttwo posts might feel uncomfortably close to total skepticism. “Wait,” you might say, “doesn’t this seem to imply that we don’t know anything about the real world, but only about our experiences?”

If I speak of objects in time and space, I am not speaking of things in themselves (since I know nothing of them), but only of things in appearance, i.e. of experience as a distinct way of cognizing objects that is granted to human beings alone. I must not say of that which I think in space or time: that it is in itself in space and time, independent of this thought of mine; for then I would contradict myself, since space and time, together with the appearances in them, are nothing existing in themselves and outside my representations, but are themselves only ways of representing, and it is patently contradictory to say of a mere way of presenting that it also exists outside our representation. The objects of the senses therefore exist only in experience; by contrast, to grant them a self-subsistent existence of their own, without experience or prior to it, is as much as to imagine that experience is also real without experience or prior to it.

There could be a way of understanding this to say something true, but it is more easily understood as asserting something deeply erroneous. Kant may in fact have both the truth and the error in mind, or perhaps he is ambivalent concerning the correct interpretation.

Consider the distinction between the way things are known by us and the way things are in themselves. It is possible to fall into error by asserting that since things are known by us in a certain way, they must be that way in themselves. Thus we know things in a general way, and thus some Platonists might conclude that things exist in themselves in a general way, but this is an error.

But another way to fall into error would be to admit that our way of knowing is distinct from the way of being, and then to conclude from the fact that our way of knowing does not correspond precisely to the way of being, that our knowledge is false, or that we do not know at all. This is the deeply erroneous claim that Kant seems to be making above.

Consider the meaning of the statement: “We know things as they are in themselves.” If we take the phrase, “as they are in themselves,” as expressing our mode of knowing adverbially, just as we might say “We know things in general terms,” and then intend to assert that our mode of knowing is the same as the mode of the being of the thing, then the statement that we know things as they are in themselves is surely false. For the meaning would be that the things exist in our knowledge in exactly the same way as they exist in themselves — thus for example it would be implied that our knowledge is not general but particular. But more precisely, it would imply that there is no distinction whatsoever between our knowledge and the thing. In other words, if we know a horse, our knowledge is actually a horse, physically and literally. And this is manifestly false.

From this we can see both the truth and the error. The truth is that we do not know things as they are in themselves in the above sense, precisely because our knowledge is distinct from the thing known. And the error would be the conclusion that therefore we do not know things at all. Kant seems most clearly to assert the error when he says, “I am not speaking of things in themselves (since I know nothing of them), but only of things in appearance.” The Kantian may insist that this follows necessarily from the truth that we do not know things as they are in themselves in the above sense.

But it is easy to see why this is wrong. We do not know things “as they are in themselves” by having a mode of knowledge identical to the mode of their being. But this does not mean that there is anything that we do not know; in fact, having an identical mode of knowing and being would precisely mean not knowing at all, but being the thing instead. In other words, it does not follow that there is any knowledge that we are missing out on; on the contrary, knowing requires a specific mode of knowing which is different from the mode of being of the thing. It is not that the difference between mode of knowing and being implies that we do not know, but rather this difference is the very condition for knowledge to exist at all. Ayn Rand rightly said of this matter:

Even apart from the fact that Kant’s theory of the “categories” as the source of man’s concepts was a preposterous invention, his argument amounted to a negation, not only of man’s consciousness, but of any consciousness, of consciousness as such. His argument, in essence, ran as follows: man is limited to a consciousness of a specific nature, which perceives by specific means and no others, therefore, his consciousness is not valid; man is blind, because he has eyes—deaf, because he has ears—deluded, because he has a mind—and the things he perceives do not exist, because he perceives them.

Again, the Kantian may insist that perhaps we know the things. But again, we are just admitting we know the things as they appear to us, not as they are in themselves. So even if we know all things, we do not know their mode of being. The response is that we can know both the things and their mode of being, but we know both according to our mode of knowing, not according to their mode of being. This is similar to knowing someone else’s mode of knowing; when you do this, you do not therefore know with their mode of knowing, but with your own. Likewise, when you know the mode of the being of things, you know not with their mode of being, but with your own mode of knowing.

How does this answer our original question? Okay, you might say, there is no proof that there is anything that we cannot know in principle. But in practice it seems clear that our knowledge is entirely superficial, and thus hardly seems to be knowledge at all.

There is a large difference, however, between the assertion, “Most of our actual knowledge is rather superficial,” and the skeptical assertion, “Our knowledge is superficial in principle, and it is therefore impossible to know things as they truly are.” The first assertion is largely correct, and the second is quite wrong. It is true that the understanding of things that we attain “automatically,” as it were, from common experience, is a superficial knowledge, and thus ordinary language about ordinary things expresses such a superficial knowledge. It does not follow that a deep knowledge of things is impossible. However, if someone does not actually have such a deep knowledge, they may also misunderstand what it would even be like to have such a knowledge; and thus for example they might suppose that it would be necessary to have a knowledge of “things in themselves” in the Kantian sense, which of course is impossible, since it would eliminate the distinction between the mode of knowing and the mode of being.

In fact, not only is it not a contradiction to assert that we can know things as they are, but it would be a contradiction to assert, “There is something which we cannot know in any way, even in principle.” For “there is something” purports to refer to the thing and assert its existence, and such reference and assertion, if true, would be a kind of knowledge. Ludwig Wittgenstein makes the similar point, “We cannot think what we cannot think; so what we cannot think we cannot say either.”

It is not, however, a contradiction to say that there are some things that we cannot know in some ways. And this is surely true.

Now what I’ve said so far is usually accepted as uncontroversial, at least when applied to the usual parts of our world, such as rivers, cars, mountains laptops, or ants. But as soon as one claims that all this applies to human minds, suddenly it gets more controversial. People often state things like this:

I am sure that I’m not just a collection of physical parts interacting, because I’m aware that I feel. I know that physical parts interacting just aren’t the kinds of things that can feel by themselves. So even though I have a physical body made of parts, and there are close correlations between my feelings and the states of my body parts, there must be something more than that to me (and others like me). So there’s a deep mystery: what is this extra stuff, where does it arise, how does it change, and so on. We humans care mainly about feelings, not physical parts interacting; we want to know what out there feels so we can know what to care about.

But consider a key question: Does this other feeling stuff interact with the familiar parts of our world strongly and reliably enough to usually be the actual cause of humans making statements of feeling like this?

What would someone mean by making the original statement that “I know that physical parts interacting just aren’t the kinds of things that can feel by themselves”? If we give this a charitable interpretation, the meaning is that “a collection of physical parts” is something many, and so is not a suitable subject for predicates like “sees” and “understands.” Something that sees is something one, and something that understands is something one.

This however is not Robin’s interpretation. Instead, he understands it to mean that besides the physical parts, there has to be one additional part, namely one which is a part in the same sense of “part”, but which is not physical. And indeed, some tend to think this way. But this of course is not helpful, because the reason a collection of parts is not a suitable subject for seeing or understanding is not because those parts are physical, but because the subject is not something one. And this would remain even if you add a non-physical part or parts. Instead, what is needed to be such a subject is that the subject be something one, namely a living being with the sense of sight, in order to see, or one with the power of reason, for understanding.

What do you need in order to get one such subject from “a collection of parts”? Any additional part, physical or otherwise, will just make the collection bigger; it will not make the subject something one. It is rather the formal cause of a whole that makes the parts one, and this formal cause is not a part in the same sense. It is not yet another part, even a non-physical one.

Reading Robin’s discussion in this light, it is clear that he never even considers formal causes. He does not even ask whether there is such a thing. Rather, he speaks only of material and efficient causes, and appears to be entirely oblivious even to the idea of a formal cause. Thus when asking whether there is anything in addition to the “collection of parts,” he is asking whether there is any additional material cause. And naturally, nothing will have material causes other than the things it is made out of, since “what a thing is made out of” is the very meaning of a material cause.

Likewise, when he says, “Does this other feeling stuff interact with the familiar parts of our world strongly and reliably enough to usually be the actual cause of humans making statements of feeling like this?”, he shows in two ways his ignorance of formal causes. First, by talking about “feeling stuff,” which implies a kind of material cause. Second, when he says, “actual cause of humans making statements” he is evidently speaking about the efficient cause of people producing sounds or written words.

In both cases, formal causality is the relevant causality. There is no “feeling stuff” at all; rather, certain things are things like seeing or understanding, which are unified actions, and these are unified by their forms. Likewise, we can consider the “humans making statements” in two ways; if we simply consider the efficient causes of the sounds, one by one, you might indeed explain them as “simple parts interacting simply.” But they are not actually mere sounds; they are meaningful and express the intention and meaning of a subject. And they have meaning by reason of the forms of the action and of the subject.

In other words, the idea of the philosophical zombie is that the zombie is indeed producing mere sounds. It is not only that the zombie is not conscious, but rather that it really is just interacting parts, and the sounds it produces are just a collection of sounds. We don’t need, then, some complicated method to determine that we are not such zombies. We are by definition not zombies if we say, think, or understanding at all.

The same ignorance of the formal cause is seen in the rest of Robin’s comments:

If yes, this is a remarkably strong interaction, making it quite surprising that physicists have missed it so far. So surprising in fact as to be frankly unbelievable. If this type of interaction were remotely as simple as all the interactions we know, then it should be quite measurable with existing equipment. Any interaction not so measurable would have be vastly more complex and context dependent than any we’ve ever seen or considered. Thus I’d bet heavily and confidently that no one will measure such an interaction.

Again, he is asking whether there is some additional part which has some additional efficient causality, and suggesting that this is unlikely. It is indeed unlikely, but irrelevant, because consciousness is not an additional part, but a formal way of being that a thing has. He continues:

But if no, if this interaction isn’t strong enough to explain human claims of feeling, then we have a remarkable coincidence to explain. Somehow this extra feeling stuff exists, and humans also have a tendency to say that it exists, but these happen for entirely independent reasons. The fact that feeling stuff exists isn’t causing people to claim it exists, nor vice versa. Instead humans have some sort of weird psychological quirk that causes them to make such statements, and they would make such claims even if feeling stuff didn’t exist. But if we have a good alternate explanation for why people tend to make such statements, what need do we have of the hypothesis that feeling stuff actually exists? Such a coincidence seems too remarkable to be believed.

First, there is no “extra feeling stuff.” There is only a way of being, namely in this case being alive and conscious. Second, there is no coincidence. Robin’s supposed coincidence is that “I am conscious” is thought to mean, “I have feeling stuff,” but the feeling stuff is not the efficient cause of my saying that I have it; instead, the efficient cause is said to be simple parts interacting simply.

Again, the mistake here is simply to completely overlook the formal cause. “I am conscious” does not mean that I have any feeling stuff; it says that I am something that perceives. Of course we can modify Robin’s question: what is the efficient cause of my saying that I am conscious? Is it the fact that I actually perceive things, or is it simple parts interacting simply? But if we think of this in relation to form, it is like asking whether the properties of a square follow from squareness, or from the properties of the parts of a square. And it is perfectly obvious that the properties of a square follow both from squareness, and from the properties of the parts of a square, without any coincidence, and without interfering with one another. In the same way, the fact that I perceive things is the efficient cause of my saying that I perceive things. But the only difference between this actual situation and a philosophical zombie is one of form, not of matter; in a corresponding zombie, “simple parts interacting simply” are the cause of its producing sounds, but it neither perceives anything nor asserts that it is conscious, since its words are meaningless.

Carroll inspires me to try to make one point I think worth making, even if it is also ignored. My target is people who think philosophical zombies make sense. Zombies are supposedly just like real people in having the same physical brains, which arose the through the same causal history. The only difference is that while real people really “feel”, zombies do not. But since this state of “feeling” is presumed to have zero causal influence on behavior, zombies act exactly like real people, including being passionate and articulate about claiming they are not zombies. People who think they can conceive of such zombies see a “hard question” regarding which physical systems that claim to feel and otherwise act as if they feel actually do feel. (And which other systems feel as well.)

The one point I want to make is: if zombies are conceivable, then none of us will ever have any more relevant info than we do now about which systems actually feel. Which is pretty much zero info! You will never have any info about whether you ever really felt in the past, or will ever feel in the future. No one part of your brain ever gets any info from any other part of your brain about whether it really feels.

The state of “feeling” is not presumed to have zero causal influence on behavior. It is thought to have precisely a formal influence on behavior. That is, being conscious is why the activity of the conscious person is “saying that they feel” instead of “producing random meaningless sounds that others mistakenly interpret as meaning that they feel.”

Regarding his point about “info,” the possession of any information at all is already a proof that one is not a zombie. Since the zombie lacks form, any correlation between one part and another in it is essentially a random material correlation, not one that contains any information. If the correlation is noticed as having any info, then the thing noticing the information, and the information itself, are things which possess form. This argument, as far as it goes, is consistent with Robin’s claim that zombies do not make sense; they do not, but not for the reasons that he posits.

There is nothing that we know of that isn’t described well by physics, and everything that physicists know of is well described as many simple parts interacting simply. Parts are localized in space, have interactions localized in time, and interactions effects don’t move in space faster than the speed of light. Simple parts have internal states that can be specified with just a few bits (or qubits), and each part only interacts directly with a few other parts close in space and time. Since each interaction is only between a few bits on a few sides, it must also be simple. Furthermore, all known interactions are mutual in the sense that the state on all sides is influenced by states of the other sides.

For example, ordinary field theories have a limited number of fields at each point in space-time, with each field having a limited number of degrees of freedom. Each field has a few simple interactions with other fields, and with its own space-time derivatives. With limited energy, this latter effect limits how fast a field changes in space and time.

As a second example, ordinary digital electronics is made mostly of simple logic units, each with only a few inputs, a few outputs, and a few bits of internal state. Typically: two inputs, one output, and zero or one bits of state. Interactions between logic units are via simple wires that force the voltage and current to be almost the same at matching ends.

As a third example, cellular automatons are often taken as a clear simple metaphor for typical physical systems. Each such automation has a discrete array of cells, each of which has a few possible states. At discrete time steps, the state of each cell is a simple standard function of the states of that cell and its neighbors at the last time step. The famous “game of life” uses a two dimensional array with one bit per cell.

This basic physics fact, that everything is made of simple parts interacting simply, implies that anything complex, able to represent many different possibilities, is made of many parts. And anything able to manage complex interaction relations is spread across time, constructed via many simple interactions built up over time. So if you look at a disk of a complex movie, you’ll find lots of tiny structures encoding bits. If you look at an organism that survives in a complex environment, you’ll find lots of tiny parts with many non-regular interactions.

Physicists have learned that we only we ever get empirical evidence about the state of things via their interactions with other things. When such interactions the state of one thing create correlations with the state of another, we can use that correlation, together with knowledge of one state, as evidence about the other state. If a feature or state doesn’t influence any interactions with familiar things, we could drop it from our model of the world and get all the same predictions. (Though we might include it anyway for simplicity, so that similar parts have similar features and states.)

Not only do we know that in general everything is made of simple parts interacting simply, for pretty much everything that happens here on Earth we know those parts and interactions in great precise detail. Yes there are still some areas of physics we don’t fully understand, but we also know that those uncertainties have almost nothing to say about ordinary events here on Earth. For humans and their immediate environments on Earth, we know exactly what are all the parts, what states they hold, and all of their simple interactions. Thermodynamics assures us that there can’t be a lot of hidden states around holding many bits that interact with familiar states.

Now it is true that when many simple parts are combined into complex arrangements, it can be very hard to calculate the detailed outcomes they produce. This isn’t because such outcomes aren’t implied by the math, but because it can be hard to calculate what math implies. When we can figure out quantities that are easier to calculate, as long as the parts and interactions we think are going on are in fact the only things going on, then we usually see those quantities just as calculated.

The point of Robin’s argument is to take a particular position in regard to the question we are revisiting in this post: everything that is done by wholes is predictable from the behavior of the parts. The argument is simply a more extended form of a point I made in the earlier post, namely that there is no known case where the behavior of a whole is known not to be predictable in such a way, and many known cases where it is certainly predictable in this way.

The title of the present post of course refers us to this earlier post. In that post I discussed the tendency to set first and second causes in opposition, and noted that the resulting false dichotomy leads to two opposite mistakes, namely the denial of a first cause on one hand, and to the assertion that the first cause does or should work without secondary causes on the other.

In the same way, I say it is a false dichotomy to set the work of form in opposition with the work of matter and disposition. Rather, they produce the same thing, both according to being and according to activity, but in different respects. If this is the case, it will be necessarily true from the nature of things that the behavior of a whole is predictable from the behavior of the parts, but this will happen in a particular way.

I mentioned an example of the same false dichotomy in the post on Robin’s book. Here again is his argument:

But consider a key question: Does this other feeling stuff interact with the familiar parts of our world strongly and reliably enough to usually be the actual cause of humans making statements of feeling like this?

If yes, this is a remarkably strong interaction, making it quite surprising that physicists have missed it so far. So surprising in fact as to be frankly unbelievable. If this type of interaction were remotely as simple as all the interactions we know, then it should be quite measurable with existing equipment. Any interaction not so measurable would have be vastly more complex and context dependent than any we’ve ever seen or considered. Thus I’d bet heavily and confidently that no one will measure such an interaction.

But if no, if this interaction isn’t strong enough to explain human claims of feeling, then we have a remarkable coincidence to explain. Somehow this extra feeling stuff exists, and humans also have a tendency to say that it exists, but these happen for entirely independent reasons. The fact that feeling stuff exists isn’t causing people to claim it exists, nor vice versa. Instead humans have some sort of weird psychological quirk that causes them to make such statements, and they would make such claims even if feeling stuff didn’t exist. But if we have a good alternate explanation for why people tend to make such statements, what need do we have of the hypothesis that feeling stuff actually exists? Such a coincidence seems too remarkable to be believed.

I am currently awake and conscious, hearing the sounds of my keyboard as I type and the music playing in the background. Robin’s argument is something like this: why did I type the previous sentence? Is it because I am in fact awake and conscious and actually heard these sounds? If in principle it is predictable that I would have typed that, based on the simple interactions of simple parts, that seems to be an entirely different explanation. So either one might be the case or the other, but not both.

Let us consider this in a simpler case. We earlier discussed the squareness of a square. Suppose someone attempted to apply Robin’s argument to squares. The equivalent argument would say this: all conclusions about squares can be proved from premises about the four lines that make it up and their relationships. So what use is this extra squareness? We might as well assume it does not exist, since it cannot explain anything.

In order to understand this one should consider why we need several kinds of cause in the first place. To assign a cause is just to give the origin of a thing in a way that explains it, while explanation has various aspects. In the linked post, we divided causes into two, namely intrinsic and extrinsic, and then divided each of these into two. But consider what would happen if we did not make the second division. In this case, there would be two causes of a thing: matter subject to form, and agent intending an end. We can see from this how the false dichotomies arise: all the causality of the end must be included in some way in the agent, since the end causes by informing the agent, and all the causality of the form must be included in some way in the matter, since the form causes by informing the matter.

In the case of the square, even the linked post noted that there was an aspect of the square that could not be derived from its properties: namely, the fact that a square is one figure, rather than simply many lines. This is the precise effect of form in general: to make a thing be what it is.

Consider Alexander Pruss’s position on artifacts. He basically asserted that artifacts do not truly exist, on the grounds that they seem to be lacking a formal cause. In this way, he says, they are just a collection of parts, just as someone might suppose that a square is just a collection of lines, and that there is no such thing as squareness. My response there was the same as my response about the square: saying that this is just a collection cannot explain why a square is one figure, nor can the same account explain the fact that artifacts do have a unity of some kind. Just as the denial of squareness would mean the denial of the existence of a unified figure, so the denial of chairness would mean the denial of the existence of chairs. Unlike Sean Carroll, Pruss seems even to recognize that this denial follows from his position, even if he is ambivalent about it at times.

Hanson’s argument about the human mind is actually rather similar to Pruss’s argument about artifacts, and to Carroll’s argument about everything. The question of whether or not the fact that I am actually conscious influences whether I say that I am, is a reference to the idea of a philosophical zombie. Robin discusses this idea more directly in another post:

Carroll inspires me to try to make one point I think worth making, even if it is also ignored. My target is people who think philosophical zombies make sense. Zombies are supposedly just like real people in having the same physical brains, which arose the through the same causal history. The only difference is that while real people really “feel”, zombies do not. But since this state of “feeling” is presumed to have zero causal influence on behavior, zombies act exactly like real people, including being passionate and articulate about claiming they are not zombies. People who think they can conceive of such zombies see a “hard question” regarding which physical systems that claim to feel and otherwise act as if they feel actually do feel. (And which other systems feel as well.)

The one point I want to make is: if zombies are conceivable, then none of us will ever have any more relevant info than we do now about which systems actually feel. Which is pretty much zero info! You will never have any info about whether you ever really felt in the past, or will ever feel in the future. No one part of your brain ever gets any info from any other part of your brain about whether it really feels.

These claims all follow from our very standard and well-established info theory. We get info about things by interacting with them, so that our states become correlated with the states of those things. But by assumption this hypothesized extra “feeling” state never interacts with anything. The actual reason why you feel compelled to assert very confidently that you really do feel has no causal connection with whether you actually do really feel. You would have been just as likely to say it if it were not true. What could possibly be the point of hypothesizing and forming beliefs about states about which one can never get any info?

We noted the unresolved tension in Sean Carroll’s position. The eliminativists are metaphysically correct, he says, but they are mistaken to draw the conclusion that the things of our common experience do not exist. The problem is that given that he accepts the eliminativist metaphysics, he can have no justification for rejecting their conclusions. We can see the same tension in Robin Hanson’s account of consciousness and philosophical zombies. For example, why does he say that they do not “make sense,” rather than asking whether or not they can exist and why or why not?

Let us think about this in more detail. And to see more clearly the issues involved, let us consider a simpler case. Take the four chairs in Pruss’s office. Is it possible that one of them is a zombie?

What would this even mean? In the post on the relationship of form and reality, we noted that asking whether something has a form is very close to the question of whether something is real. I really have two hands, Pruss says, if my hands have forms. And likewise chairs are real chairs if they have the form of a chair, and if they do not, they are not real in the first place, as Pruss argues is the case.

The zombie question about the chair would then be this: is it possible that one of the apparent chairs, physically identical to a real chair, is yet not a real chair, while the three others are real?

We should be able to understand why someone would want to say that the question “does not make sense” here. What would it even be like for one of the chairs not to be a real chair, especially if it is posited to be identical to all of the others? In reality, though, the question does make sense, even if we answer that the thing cannot happen. In this case it might actually be more possible than in other cases, since artifacts are in part informed by human intentions. But possible or not, the question surely makes sense.

Let us consider the case of natural things. Consider the zombie oak tree: it is physically identical to an oak tree, but it is not truly alive. It appears to grow, but this is just the motion of particles. There are three positions someone could hold: no oak trees are zombie oaks, since all are truly alive and grow; all oak trees are zombies, since all are mere collections of particles; and some are alive and grow, while others are zombies, being mere collections of particles.

Note that the question does indeed make sense. It is hard to see why anyone would accept the third position, but if the first and second positions make sense, then the third does as well. It has an intelligible content, even if it is one that we have no good arguments for accepting. The argument that it does not make sense is basically the claim that the first and second positions are not distinct positions: they do not say different things, but the same thing. Thus the the third would “not make sense” insofar as it assumes that the first and second positions are distinct positions.

Why would someone suppose that the first and second positions are not distinct? This is basically Sean Carroll’s position, since he tries to say both that eliminativists are correct about what exists, but incorrect in denying the existence of common sense things like oak trees. It is useful to say, “oak trees are real,” he says, and therefore we will say it, but we do not mean to say something different about reality than the eliminativists who say that “oak trees are not real but mere collections of particles.”

But this is wrong. Carroll’s position is inconsistent in virtually the most direct possible way. Either oak trees are real or they are not; and if they are real, then they are not mere collections of particles. So both the first and second positions are meaningful, and consequently also the third.

The second and third positions are false, however, and the meaningfulness of this becomes especially clear when we speak of the human case. It obviously does make sense to ask whether other human beings are conscious, and this is simply to ask whether their apparent living activities, such as speaking and thinking, are real living activities, or merely apparent ones: perhaps the thing is making sounds, but it is not truly speaking or thinking.

Let us go back to the oak tree for a moment. The zombie oak would be one that is not truly living, but its activities, apparently full of life, are actually lifeless. In order to avoid this possibility, and out of a zeal for form which is not according to knowledge, some assert that the activities of an oak cannot be understood in terms of the activities of the parts. There is a hint of this, perhaps, in this remark by James Chastek:

Consciousness is just the latest field where we are protesting that something constitutes a specific difference from some larger genus, but if it goes the way the others have gone, in fifty years no one will even remember the controversy or bother to give the fig-leaf explanations of it being emergent or reductive. No one will remember that there is a difference to explain. Did anyone notice in tenth-grade biology that life was explained entirely in terms of non-living processes? No. There was nothing to explain since nothing was noticed.

Chastek does not assert that life cannot be “explained entirely in terms of non-living processes,” in the manner of tenth-grade biology, but he perhaps would prefer that it could not be so explained. And the reason for this would be the idea that if everything the living thing does can be explained in terms of the parts, then oak trees are zombies after all.

But this idea is mistaken. Look again at the square: the parts explain everything, except the fact that the figure is one figure, and a square. The form of a square is indeed needed, precisely in order that the thing will actually be a whole and a square.

Likewise with the oak. If an oak tree is made out of parts, then since activity follows being, it should be unsurprising that in some sense its activities themselves will be made out of parts, namely the activities of its parts. But the oak is real, and its activities are real. And just as oaks really exist, so they really live and grow; but just as the living oak has parts which are not alive in themselves, such as elements, so the activity of growth contains partial activities which are not living activities in themselves. What use is the form of an oak, then? It makes the tree really an oak and really alive; and it makes its activities living activities such as growth, rather than being merely a collection of non-living activities.

We can look at human beings in the same way, but I will leave the details of this for another post, since this one is long enough already.

While the name “eliminativism” is used particularly with respect to the denial of the reality of consciousness or various mental conditions, we could define it more generally as the tendency to explain something away rather than explaining it. The motive for this would be that someone believes that reality does not have the principles needed in order to explain the thing; so it is necessary for them to explain it away instead. In this way we noted that Daniel Dennett denies the existence of consciousness. Since every being is objective, in his view, reality does not have any principle which could explain something subjective. Therefore it is necessary for him to explain away subjectivity.

If we take eliminativism in this general way, it will turn out that Parmenides is the ultimate eliminativist. According to Parmenides, not only is there nothing but being, but nothing can be distinct from being in any way, even in concept. Thus anything which appears to be conceptually distinct from being, including ourselves and all the objects of our common experience, is nothing but an illusion deluding itself. And ultimately nothing at all, since even illusions cannot be something other than being.

Parmenides comes to this conclusion in the same general way as Dennett, namely because it seems to him that reality cannot have any principle which could explain things as they are. It is evident that there cannot be anything besides being; thus if something seems distinct from being in any way, there is no principle capable of explaining it.

Suppose we have two elements, as for example water and earth (not that these are really elements.) How do we make something out of the elements? We can consider two different possible ways that this could happen.

Suppose that when we combine one part water and one part earth, we get mud, and when we combine one part water and two parts earth, we get clay. Thus clay and mud are two different composite bodies that can be made from our elements.

But we could also say, “Although clay and mud are made of earth and water, they are also something new. Consequently we can work out the laws governing them by experience, but we cannot expect to work them out just from the laws governing earth and water.”

These two claims are basically opposed to one another, and we should not expect that both would be true, at least in any particular instance. It might be that one is true in some cases and the other is true in some cases, or it might be that one side is always true. But in any case one will be true and not the other, in each particular situation.

Someone might argue that the first claim must be always true in principle. If water behaves one way by itself, and another way when it is combined with earth, then you haven’t sufficiently specified the behavior of water without including how it behaves when it is beside earth, or mixed with earth, or combined in whatever way. So once you have completely specified the behavior of water, you have specified how it behaves when combined with other things.

But this way of thinking is artificial. If water follows an inverse square law of gravity by itself, but an entirely different mathematical law when it is combined with earth, rather than saying that the entirely different law is a special case governing water, we should just admit that the different law is a law governing clay and mud, but not water. On the other hand, it is not unreasonable to include various potential interactions in your laws governing water, rather than only considering how water behaves in perfect isolation. Thus for example one would want to say that water suffers gravitational effects from all other bodies, rather than simply saying that water attracts itself. Nonetheless, even if the distinction is somewhat rough, there is a meaningful distinction between situations where the laws governing the elements also govern the composites, and situations where we need new laws for the composites.

In a second way, the second claim is almost always true. If we consider our laws as practical methods for predicting the behavior of a physical system, in practice we will almost always need special laws to predict the behavior of a complex composite, if only because it would be too complex and time consuming to predict the behavior of the composite using laws governing only the parts. Thus people who wish to predict the weather use generalizations based on the experience of weather, rather than trying to predict the weather simply by considering more general laws of physics, despite believing that the weather is in fact a consequence of such general laws.

In a third way, the first claim is true at least frequently, and possibly always. If we consider the behavior of a bicycle or a computer, not with respect to general questions such as “can I ride it?” or “can it calculate the square root of two?”, but with respect to the physical movement of the parts, there are good reasons to think that the behavior of the whole can be determined from the behavior of the parts of which it is composed. For these are human inventions, and although experience is involved in such inventions, people make guesses about new behavior largely from their understanding of how the parts behave which they plan to put together. So if the whole behaved in ways which are significantly unpredictable from the behavior of the parts, we would not expect such inventions to work. Likewise, as said above, there is little reason to doubt that the weather results from general principles of physics that apply to earth, air, water, and so on.

I say “possibly always” above, because there is no case where the second claim is known to be true in this sense, and many instances, as noted, where the first is known or reasonably believed to be the case. Additionally, one can give reasons in principle for expecting the first claim to be true in this way, although this is a matter for later consideration.

An important objection to this possibility is that the fact that the second claim is always true in the first way mentioned above, seems to imply that the first claim cannot be true even in the third way, at least in some cases. In particular, the conscious behavior of living things, and especially human free will, might seem inconsistent with the idea that the physical behavior of living things is in principle predictable from laws governing their elements.

Take a stock example of reductive scientific explanation like the reduction of sound to compression waves, color to surface reflectance properties, or heat and cold to molecular motion. The way these explanations work is by treating the appearance that sound, color, heat and cold present to us in conscious experience as mere appearance, as a projection of the mind that corresponds to nothing in objective, mind-independent reality. What common sense understands by color, sound, heat and cold — the way red looks, the way a musical note sounds, the way a hot stove feels, and so forth — is held to have no objective reality, any more than the redness a person unknowingly wearing red-tinted contact lenses thinks he sees in all the objects around him really exists in those objects. Instead, color is for scientific purposes essentially redefined by the method in terms of the surface reflectance properties that cause in us the subjective appearance of color; sound redefined in terms of the compression waves that cause in us the subjective appearance of sound; and heat and cold redefined in terms of the molecular motion that causes in us the subjective appearance of heat and cold.

Thus, as common sense understands color, sound, heat and cold, etc., the reductive method ends up treating the world as essentially colorless, soundless, devoid of temperature, etc. What the method calls “color,” “sound,” “heat” and “cold” is in fact something different from what the man on the street thinks of when he hears these terms. The “red” that the method says exists in the material world is just the tendency of an object to absorb certain wavelengths of light and to reflect others. The “red” that the man on the street thinks exists in the object does not really exist in the object itself at all but only in his perceptual experience of the object. The “heat” that the method says really exists in the material world is just the motion of molecules. The “heat” that the man on the street thinks exists in the object does not really exist in the object at all but only in his perceptual experience of the object. And so forth.

Now, Nagel’s point is not that there is something wrong per se with overthrowing common sense in this way. It is rather that whatever value this method has, it cannot coherently be applied to the explanation of conscious experience itself. If the reductive method involves ignoring the appearances of a thing and redefining the thing in terms of something other than the appearances, then since our conscious experience of the world just is the way the world appears to us, to ignore the appearances is in this case just to ignore the very phenomenon to be explained rather than to explain it. Consciousness is for this reason necessarily and uniquely resistant to explanation via the same method scientific reductionism applies to everything else. For the application of the method in this case, writes Nagel, “does not take us nearer to the real nature of the phenomenon: it takes us farther away from it.” To treat the appearances as essentially “subjective” or mind-dependent is precisely to make them incapable of explanation in entirely “objective” or mind-independent terms.

In spite of its strident tone, I am grateful for Daniel Dennett’s response to my review because it enables me to make the differences between us crystal clear. I think we all really have conscious states. To remind everyone of this fact I asked my readers to perform the small experiment of pinching the left forearm with the right hand to produce a small pain. The pain has a certain sort of qualitative feeling to it, and such qualitative feelings are typical of the various sorts of conscious events that form the content of our waking and dreaming lives. To make explicit the differences between conscious events and, for example, mountains and molecules, I said consciousness has a first-person or subjective ontology. By that I mean that conscious states only exist when experienced by a subject and they exist only from the first-person point of view of that subject.

Such events are the data which a theory of consciousness is supposed to explain. In my account of consciousness I start with the data; Dennett denies the existence of the data. To put it as clearly as I can: in his book, Consciousness Explained, Dennett denies the existence of consciousness. He continues to use the word, but he means something different by it. For him, it refers only to third-person phenomena, not to the first-person conscious feelings and experiences we all have. For Dennett there is no difference between us humans and complex zombies who lack any inner feelings, because we are all just complex zombies.

I think most readers, when first told this, would assume that I must be misunderstanding him. Surely no sane person could deny the existence of feelings. But in his reply he makes it clear that I have understood him exactly. He says, “How could anyone deny that!? Just watch…”

Dennett is obviously wrong about consciousness. But what about color, sound, heat, and cold? Is it true that “reductive scientific explanation” holds that these things are a “mere appearance” that “correspond to nothing in objective, mind-independent reality?”

Feser may be quite honest personally in his description of what he considers to be two opposing views. But it seems to me that he is inheriting this description from a long tradition of putting Aristotle and common sense, on the one hand, into an unnecessary opposition with modern scientific views on the other. I think that this tradition is in essence wishful thinking: this tradition came to be historically through the efforts of people who wished for disagreement between Aristotle and modern science.

I touched on this wish in an earlier post when I said that John Locke’s understanding of secondary qualities “is actually mostly true, and mostly consistent with the philosophy of Aristotle, even though Locke would likely wish that the latter were not the case.” The early moderns did differ from Aristotle regarding the purpose of the sciences, as I pointed out here in the case of Francis Bacon. Having a different purpose requires employing different means. Consequently it was favorable for their purposes to emphasize their disagreements with the philosophy of Aristotle, regardless of how much agreement or disagreement existed in reality when the positions themselves are properly understood. If people could be persuaded to abandon Aristotelian thought and focus on the new science, the purposes of the new science would be more easily obtained.

Let us ask the question directly: if color for example consists in the reflectance properties of a surface, does this mean that colors as we see them are “mere appearances” that have no objective reality? Elsewhere, Feser says that this view implies that “Objectively there are only colorless, odorless, soundless, tasteless, meaningless particles in fields of force.”

The scientist can presumably reply in this way: Color consists in surface reflectance properties. These properties are objective properties of physical objects in the world. So color is an objective property of physical objects in the world.

Feser’s response can be found in the original quotation above:

What common sense understands by color, sound, heat and cold — the way red looks, the way a musical note sounds, the way a hot stove feels, and so forth — is held to have no objective reality, any more than the redness a person unknowingly wearing red-tinted contact lenses thinks he sees in all the objects around him really exists in those objects. Instead, color is for scientific purposes essentially redefined by the method in terms of the surface reflectance properties that cause in us the subjective appearance of color; sound redefined in terms of the compression waves that cause in us the subjective appearance of sound; and heat and cold redefined in terms of the molecular motion that causes in us the subjective appearance of heat and cold.

Of course, the scientist would say that when a person wears red tinted contact lenses, the physical objects around him do not have the properties that constitute red, and consequently it is true that the objects are not objectively red. But other objects like red apples and the like do have those properties, and so they are objectively red. The two cases are not the same. Feser is replying by saying that whether he wants to or not, the scientist is denying the existence of red as we know it.

According to Feser, “what common sense understands by color” is something like “the way red looks,” and it is this to which, according to him, the scientist is denying objective existence. This is to say, if it true that red bodies have a certain way of reflecting light, and this fact is all there is in the body which explains why red bodies look red, Feser would say that this means that “the body is red” is a false statement. This is necessary for his position to be true: “the body is red” has to be actually false in the sense that we normally understand it, since he made the comparison with red tinted glasses, where in fact it is false that the body is red.

What do we mean when we say that something is red? We don’t just mean that it looks a certain way, because we know that sometimes things appear to be a color which they are not, as in the case of the tinted glasses. We don’t mean that it looks some way; we mean that it is that way. Take something that looks red. If we say that it is actually red, we mean that it actually is the way it looks.

All this is true, but it causes Feser to fall into error. “This is actually red” no more describes the nature of red than “this looks red” does. We know how red things look, because we experience it directly. But this experience is not a description. It is not something that can be true or false, so that we can say “surface reflectance is a false description of this experience.” It is a sensible experience, not a claim to truth or falsehood, and we consider sensible experiences accurate when they do not mislead us. Red tinted glasses do mislead us, and so we consider those experiences “false”, and say that the things are not really red. But even if color consists in surface reflectance properties, the experience of color never misled us. It never said, “This is not a reflectance property,” because it never said anything at all. It was not a statement but a sensation.

In order to determine whether something is actually red, we do not turn sensation into a description and check whether the thing matches that description. This is probably not even possible. We simply recognize that “this is actually red” when it looks red to a normal person in normal circumstances. And this is true regardless of what is present in the body that causes red things to look red to us, whether that is the properties of the surface or something else. Thus the scientist has no need to deny the objectivity of color, nor to deny his physical explanation of color.

Feser may actually have a different concern about objectivity, not merely whether statements about color are true or false. Are the distinctions in question natural distinctions, or are they essentially arbitrary from an objective point of view? Is the line between blue and green a natural one, or do our senses make that distinction in a basically arbitrary manner? Locke and others called certain qualities “secondary” because it seemed to them that the distinctions in question were basically arbitrary. We have good evidence that at least in some cases, they were right. An object feels hot or cold depending on the current condition of the one who feels it, without having to change from “being objectively hot” to “being objectively cold.” While the evidence is less conclusive in the case of color, something similar appears to be the case there. The line between different colors is in a different place for different people, as is most evidently the case in colorblind persons, and much more are the dividing lines in different places for different species of animal. This means that we have some reason to believe that green and blue things are objectively distinct, but that this objective distinction is much like the objective distinction between persons who are under six feet tall and persons who are over six feet tall. The distinction itself is objective, but the choice of distinction is basically arbitrary, if the thing is considered in itself.